scholarly journals Tsunamis boulders on the rocky shores of Minorca (Balearic Islands)

2018 ◽  
Vol 18 (7) ◽  
pp. 1985-1998 ◽  
Author(s):  
Francesc Xavier Roig-Munar ◽  
Joan Manuel Vilaplana ◽  
Antoni Rodríguez-Perea ◽  
José Ángel Martín-Prieto ◽  
Bernadí Gelabert
Keyword(s):  
Sea Level ◽  
High Probability ◽  
Numerical Models ◽  
Balearic Islands ◽  
Eastern Coast ◽  
Rocky Shores ◽  
Tsunami Waves ◽  
South Eastern ◽  
Storm Waves ◽  
Run Up

Abstract. Large boulders have been found on marine cliffs of 24 study areas on Minorca, in the Balearic archipelago. These large imbricated boulders of up to 229 t are located on platforms that comprise the rocky coastline of Minorca, several tens of meters from the edge of the cliff, up to 15 m above the sea level and kilometers away from any inland escarpment. They are mostly located on the south-eastern coast of the island, and numerical models have identified this coastline as a zone with a high probability of tsunami impact. The age of the boulders of the studied localities range between 1574 AD and recent times, although most of them are concentrated around the year 1790 AD. Although some storm waves might play a role in their dislodging, the distribution of the boulder sites along the Balearic Islands, the degree and direction of imbrication and the run-up necessary for their placement suggest transport from northern African tsunami waves that hit the coastline of Minorca.

scholarly journals Tsunamis boulders on the rocky shores of Minorca (Balearic Islands)

2017 ◽  
Author(s):  
Francesc X. Roig-Munar ◽  
Josep M. Vilaplana ◽  
Antoni Rodríguez-Perea ◽  
José A. Martín-Prieto ◽  
Bernadí Gelabert
Keyword(s):  
Sea Level ◽  
North Africa ◽  
Numerical Models ◽  
Balearic Islands ◽  
Rocky Shores ◽  
Impact Zone ◽  
Tsunami Waves ◽  
Southeast Coast ◽  
Historical Tsunamis ◽  
Run Up

Abstract. Large boulders have been found on marine cliffs of 24 study areas of Minorca, Balearic Archipelago. These large imbricated boulders, of up to 229 tonnes, are located on platforms that conform the rocky coastline of Minorca, several tenths of meters from the edge of the cliff, up to 15 m above the sea level, and kilometres away from any inland escarpment. They are mostly located on the southeast coast of the island, and numerical models have identified this coastline as a high tsunami impact zone. The age of the boulders in most of the studied localities show a good correlation with historical tsunamis. Age of the boulders, direction of imbrication and estimation of run-up necessary for their placement, indicate dislodging and transport by North Africa tsunami waves that hit the coastline of Minorca.

scholarly journals Tsunami Boulders on the Rocky Coasts of Ibiza and Formentera (Balearic Islands)

2019 ◽  
Vol 7 (10) ◽  
pp. 327 ◽  
Author(s):  
Francesc Xavier Roig-Munar ◽  
Antonio Rodríguez-Perea ◽  
José Angel Martín-Prieto ◽  
Bernadi Gelabert ◽  
Joan Manuel Vilaplana
Keyword(s):  
Numerical Models ◽  
Western Mediterranean ◽  
Balearic Islands ◽  
Tsunami Waves ◽  
Documentary Sources ◽  
The North ◽  
Submarine Earthquakes ◽  
Storm Wave ◽  
Run Up ◽  
Study Sites

Large boulders have been found in marine cliffs from 7 study sites on Ibiza and Formentera Islands (Balearic Islands, Western Mediterranean). These large boulders of up to 43 t are located on platforms that form the rocky coastline of Ibiza and Formentera, several tens of meters from the edge of the cliff, up to 11 m above sea level and several kilometers away from any inland escarpment. Despite than storm wave height and energy are higher from the northern direction, the largest boulders are located in the southern part of the islands. The boulders are located in the places where numerical models of tsunami simulation from submarine earthquakes on the North African coast predict tsunami impact on these two islands. According to radiocarbon data and rate of growth of dissolution pans, the ages of the boulders range between 1750 AD and 1870 AD. Documentary sources also confirm a huge tsunami affecting the SE coast of Majorca (the largest Balearic Island) in 1756. The distribution of the boulders sites along the islands, the direction of imbrication and the run-up necessary for their placement suggest that they were transported from northern African tsunami waves that hit the coastline of Ibiza and Formentera Islands.

Tsunami Hazard of the Caspian Sea

2021 ◽  
Author(s):  
Alisa Medvedeva ◽  
Igor Medvedev
Keyword(s):  
Sea Level ◽  
Caspian Sea ◽  
Tsunami Hazard ◽  
Seismic Sources ◽  
Deterministic Approach ◽  
The Caspian Sea ◽  
Tsunami Waves ◽  
The Mean ◽  
Run Up ◽  
Sea Coast

<p>A regional model of tsunami seismic sources in the zone of the Main Caucasian thrust has been developed. The parameters of probable models of seismic sources and their uncertainties were estimated based on the available data on historical earthquakes and active faults of the region. The scenario modeling technique was used for the tsunami zoning of the Caspian Sea coast. The time period covered by the model catalog of earthquakes used to calculate the generation and propagation of tsunamis is about 20 000 years, which is longer than the recurrence periods of the strongest possible earthquakes. The recurrence graphs of the calculated maximum tsunami heights for the entire sea coast were plotted. On their basis, the maximum heights of tsunami waves on the coast were calculated with recurrence periods of 250, 500, 1000 and 5000 years and the corresponding survey maps of the tsunami zoning of the Caspian Sea were created. The algorithm for calculating the tsunami run-up on the coast is improved, taking into account the residual (postseismic) displacements of the bottom and land relief. Estimates of tsunami hazard for the coast near the city of Kaspiysk were carried out: within the framework of the deterministic approach, the maximum wave heights and run-up distance were calculated. It is shown that the deterministic approach slightly overestimates the maximum heights of tsunami waves with certain return periods. It is shown that changes in the mean sea level can affect the features of the propagation of tsunami waves in the Caspian Sea. Thus, at an average sea level of -25-26 m, the Kara-Bogaz-Gol Bay is linked with the entire sea through a narrow strait. It leads to the propagation of tsunami waves into the water area of the bay and a decrease in wave height on the eastern coast of the sea. When the mean sea level decreases below -27 m, the positive depths in the strait disappear and water exchange through the strait stops, and the wave height in this part of the sea increases.</p>

On the origin of multiple tsunami inundation of the archaeological site of Ognina (Sicily): Numerical models and field geological data

2021 ◽  
Author(s):  
Giovanni Scardino ◽  
Angela Rizzo ◽  
Vincenzo De Santis ◽  
Despo Kyriakoudi ◽  
Alessio Rovere ◽  
...  
Keyword(s):  
Sea Level ◽  
Tsunami Wave ◽  
Numerical Models ◽  
Narrow Channel ◽  
High Energy ◽  
Central Mediterranean ◽  
Geological Evidence ◽  
Tsunami Modelling ◽  
South Eastern ◽  
The Past

<p>South-eastern Sicily is among the most seismically active areas of the central Mediterranean. As such, it is marked by a high level of crustal seismicity producing major earthquakes (up to Mw ∼7), and consequent several earthquake-generated tsunami, which have affected the Ionian coast of South-eastern Sicily in historical times. These tsunami events left geomorphic imprints such as large boulders or high-energy deposits along the Sicily coasts. In Ognina, a small town located 20 km south of Siracusa, high-energy deposits were correlated with three tsunami events that struck this coast on 21 July 365 Common Era (CE), 4 February 1169 CE, and 11 January 1693 CE. The deposits are detected in the inner part of a narrow channel, that is thought to have funnelled the tsunami flow energy. In this work, numerical models have been performed to simulate the tsunami impacts, considering the most probable tsunamogenic sources described in literature and integrating them with the past sea-level positions. To this end, we used Delft Dashboard, Delft 3d-FLOW and XBeach. A reconstruction of the past topography of Ognina coast was performed through geological and historical information, in order to model the tsunami wave propagation in the ancient landscape. Geological evidence with model results, under different scenarios, allow us to benchmark fault location and displacement scenarios. Modelling results indicate that the 1693 tsunami event was stronger than others impacting the Ognina area, determining significant inland flooding in the narrow channel. Moreover, simulations show that the most probable tsunamogenic sources of 1693 and 1169 tsunami events could be attributed to Western Fault dislocations occurred off-shore of Ognina area, rather than the other tsunamogenic sources described in literature, located off-shore of Catania and Siracusa. Modelling of 365 AD event shows a long period for the tsunami wave that determined the sedimentation on the lower units in the outcrop. For each of the three tsunami events, models of high-energy deposition match with position and thickness of high-energy layers detected in the field. The results of this study show how a combined approach between geological evidence and tsunami modelling could be a suitable tool for the attribution of tsunami deposits connected to specific tsunamogenic sources.</p><p> </p><p>Keyword: tsunami; earthquake; faults; flooding; sea-level</p>

scholarly journals Tsunami run-up estimation based on a hybrid numerical flume and a parameterization of real topobathymetric profiles

2017 ◽  
Author(s):  
Íñigo Aniel-Quiroga ◽  
Omar Quetzalcóatl ◽  
Mauricio González ◽  
Louise Guillou
Keyword(s):  
Numerical Models ◽  
Fluid Model ◽  
Coupled Model ◽  
Tsunami Hazard ◽  
Water Model ◽  
Tsunami Waves ◽  
Small Areas ◽  
Prone Area ◽  
Run Up ◽  
Tsunami Run Up

Abstract. Tsunami run-up is a key value to determine when calculating and assessing the tsunami hazard in a tsunami-prone area. Run-up is accurately calculated by means of numerical models, but these models require high-resolution topobathymetric data, which are not always available, and long computational times. These drawbacks restrict the application of these models to the assessment of small areas. As an alternative method, to address large areas, empirical formulae are commonly applied to estimate run-up. These formulae are based on numerical or physical experiments on idealized geometries. In this paper, a new methodology is presented to calculate tsunami hazard at large scales. This methodology determines the tsunami flooding by using a coupled model that combines a nonlinear shallow water model (2D-H) and a volume-of-fluid model (RANS 2D-V) and applies the optimal numerical scheme in each phase of the tsunami generation-propagation-inundation process. The hybrid model has been widely applied to build a tsunami run-up database (TRD). The aim of this database is to form an interpolation domain with which to estimate the tsunami run-up of new scenarios without running a numerical simulation. The TRD was generated by simulating the propagation of parameterized tsunami waves on real non-scaled profiles. A database and hybrid numerical model were validated using real and synthetic scenarios. The new methodology provides feasible estimations of the tsunami run-up; engineers and scientists can use this methodology to address tsunami hazard at large scales.

scholarly journals Estimates of Amplitude Characteristics of Tsunami Wave Run-Up in Various Areas of the Black Sea Coast

2021 ◽  
Author(s):  
A. Yu. Belokon ◽  
Keyword(s):  
Wave Propagation ◽  
Sea Level ◽  
Black Sea ◽  
Tsunami Wave ◽  
Computational Modelling ◽  
Wave Model ◽  
The Black Sea ◽  
Tsunami Propagation ◽  
Tsunami Waves ◽  
Run Up

This paper is devoted to computational modelling of tsunami wave propagation and runup to the shore for some points on the Russian, Turkish, Bulgarian and Ukrainian coasts of the Black Sea. The nonlinear long wave model was used to solve the problem of wave propagation from hydrodynamic tsunami sources, which can constitute the greatest potential danger for the studied coast areas. The hydrodynamic sources were set in the form of an elliptical elevation, the parameters of which were chosen according to the sea level response to an underwater earthquake of magnitude 7. All the sources were located in seismically active areas, where tsunamigenic earthquakes had already occurred, along the 1500 m isobath. Near each of the studied points in the area above 300 m depths, we calculated marigrams, i.e. time-series of sea level fluctuations caused by the passage of waves. Then, a one-dimensional problem of tsunami propagation and run-up on the coast was solved for each of the points under study, where the obtained marigrams were used as boundary conditions. Peculiarities of tsunami wave propagation have been shown depending on the bottom and land relief in the studied areas of the Black Sea. Estimates have been obtained of the sea level maximum rise and fall during surge and subsequent coastal drainage for the characteristic scales of relief irregularity at different points. For possible tsunamigenic earthquakes, the largest splashes may occur in the region of Yalta (2.15 m), Cide (1.9 m), Sevastopol (1.4 m), and Anapa (1.4 m). Tsunami propagation in the Feodosiya and Varna coastal areas is qualitatively similar, with maximum wave heights of 0.64 m and 0.46 m, respectively. The coastlines of Evpatoriya (0.33 m) and Odessa (0.26 m) are least affected by tsunami waves due to the extended shelf.

scholarly journals Active tectonics along the submarine slope of south-eastern Sicily and the source of the 11 January 1693 earthquake and tsunami

2012 ◽  
Vol 12 (5) ◽  
pp. 1311-1319 ◽  
Author(s):  
A. Argnani ◽  
A. Armigliato ◽  
G. Pagnoni ◽  
F. Zaniboni ◽  
S. Tinti ◽  
...  
Keyword(s):  
Tide Gauge ◽  
Active Tectonics ◽  
Historical Earthquakes ◽  
Fault System ◽  
Tide Gauge Records ◽  
Submarine Slide ◽  
Tsunami Waves ◽  
South Eastern ◽  
Run Up ◽  
Historical Accounts

Abstract. South-eastern Sicily has been affected by large historical earthquakes, including the 11 January 1693 earthquake, considered the largest magnitude earthquake in the history of Italy (Mw = 7.4). This earthquake was accompanied by a large tsunami (tsunami magnitude 2.3 in the Murty-Loomis scale adopted in the Italian tsunami catalogue by Tinti et al., 2004), suggesting a source in the near offshore. The fault system of the eastern Sicily slope is characterised by NNW–SSE-trending east-dipping extensional faults active in the Quaternary. The geometry of a fault that appears currently active has been derived from the interpretation of seismic data, and has been used for modelling the tsunamigenic source. Synthetic tide-gauge records from modelling this fault source indicate that the first tsunami wave polarity is negative (sea retreat) in almost all the coastal nodes of eastern Sicily, in agreement with historical observations. The outcomes of the numerical simulations also indicate that the coastal stretch running from Catania to Siracusa suffered the strongest tsunami impact, and that the highest tsunami waves occurred in Augusta, aslo in agreement with the historical accounts. A large-size submarine slide (almost 5 km3) has also been identified along the slope, affecting the footwall of the active fault. Modelling indicates that this slide gives non-negligible tsunami signals along the coast; though not enough to match the historical observations for the 1693 tsunami event. The earthquake alone or a combination of earthquake faulting and slide can possibly account for the large run up waves reported for the 11 January 1693 event.

Evidence of tsunami deposits in East Tunisia coastline contemporaneous of the AD 365 Crete earthquake: Field data and modelling 

2021 ◽  
Author(s):  
Nejib Bahrouni ◽  
Mustapha Meghraoui ◽  
Hafize Başak Bayraktar ◽  
Stefano Lorito ◽  
Mohamed Fawzi Zagrarni ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Eastern Coast ◽  
Tsunami Deposits ◽  
Alluvial Deposits ◽  
Tsunami Waves ◽  
Sedimentary Deposits ◽  
Beach Rock ◽  
Hazard And Risk ◽  
Run Up ◽  
Crete Earthquake

<p>New field investigations along the East Tunisian near Sfax coastline reveal sedimentary deposits that may account for a catastrophic event. The sedimentary unit is made of sand coarse gravels, limestone beach-rock, mixed with broken shells of marine gastropods and lamellibranch mollusks, bones and organic matter. Near Thyna, at El Amra site located north of Sfax city, 3.2 m to 3.6 m high late Quaternary coastal terraces are spread over the coastline; they contain a catastrophic deposit that often cover archeological sites of the Roman period. The stratigraphic units show a succession of sandy-silty paleosol truncated by 40 to 70-cm-thick catastrophic unit which is covered in some sites by fire remains overlain by a relatively thin (~10 cm) sandy-silty aeolian unit. The sedimentary succession ends with about 1-m-thick of alluvial deposits and paleosol units. Charcoal samples collected at 10 cm below and 4 cm above the catastrophic units provide radiocarbon dating 236 - 385 cal AD and 249 – 541 cal AD (2s), respectively. Radiocarbon ages bracket the catastrophic unit that may refer to the major tsunamigenic earthquake of 21 July 365 (Mw ~ 8) in west Crete (Greece) reported to have inundated coastlines of Sabratha in Libya and Alexandria in Egypt. The nonlinear shallow water Tsunami-HySEA code is used to perform numerical modelling using 2 different seismic sources comparable to that of the AD 365 Crete earthquake. They feature 2 principal mechanisms that accommodate the Nubia-Aegean convergence along the Hellenic Arc, namely a shallowly dipping thrust-faulting on the subduction interface, as well as a steeper splay faulting in the overriding material. The maximum tsunami wave heights distribution calculated along the Tunisia coast peak in both cases at about 3 meters. The run-up caused by these sources, also considering that we have used uniform slip on the causative fault, can be significantly higher. This proves that the tsunami waves may have reached Tunisia where several coastal cities where severely damaged and reported to have stopped their economic activity. With the identification of the 365 tsunami deposits in eastern coast of Tunisia, the tsunami hazard and risk associated with a major earthquake from the western Hellenic subduction zone cannot be ruled out.</p>

scholarly journals Tsunami run-up estimation based on a hybrid numerical flume and a parameterization of real topobathymetric profiles

2018 ◽  
Vol 18 (5) ◽  
pp. 1469-1491 ◽  
Author(s):  
Íñigo Aniel-Quiroga ◽  
Omar Quetzalcóatl ◽  
Mauricio González ◽  
Louise Guillou
Keyword(s):  
Numerical Models ◽  
Fluid Model ◽  
Coupled Model ◽  
Tsunami Hazard ◽  
Water Model ◽  
Tsunami Waves ◽  
Small Areas ◽  
Prone Area ◽  
Run Up ◽  
Tsunami Run Up

Abstract. Tsunami run-up is a key value to determine when calculating and assessing the tsunami hazard in a tsunami-prone area. Run-up can be accurately calculated by means of numerical models, but these models require high-resolution topobathymetric data, which are not always available, and long computational times. These drawbacks restrict the application of these models to the assessment of small areas. As an alternative method, to address large areas empirical formulae are commonly applied to estimate run-up. These formulae are based on numerical or physical experiments on idealized geometries. In this paper, a new methodology is presented to calculate tsunami hazard at large scales. This methodology determines the tsunami flooding by using a coupled model that combines a nonlinear shallow water model (2D-H) and a volume-of-fluid model (RANS 2D-V) and applies the optimal numerical models in each phase of the tsunami generation–propagation–inundation process. The hybrid model has been widely applied to build a tsunami run-up database (TRD). The aim of this database is to form an interpolation domain with which to estimate the tsunami run-up of new scenarios without running a numerical simulation. The TRD was generated by simulating the propagation of parameterized tsunami waves on real non-scaled profiles. A database and hybrid numerical model were validated using real and synthetic scenarios. The new methodology provides feasible estimations of the tsunami run-up; engineers and scientists can use this methodology to address tsunami hazard at large scales.

scholarly journals Intermittent but Rapid Changes to Coastal Landscapes: The Tsunami and El Niño Wave-Formed Sea Arch at Laie Point, Oahu, Hawaii, U.S.A.

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 147
Author(s):  
Benjamin R. Jordan
Keyword(s):  
El Niño ◽  
El Nino ◽  
Sand Dunes ◽  
Tsunami Source ◽  
Tsunami Waves ◽  
Storm Waves ◽  
The Pacific ◽  
Coastal Landscapes ◽  
Wave Heights ◽  
First Time

Kukuiho’olua Island is an islet that lies 164 m due north of Laie Point, a peninsula of cemented, coastal, Pleistocene and Holocene sand dunes. Kukuiho’olua Island consists of the same dune deposits as Laie Point and is cut by a sea arch, which, documented here for first time, may have formed during the 1 April 1946 “April Fools’s Day Tsunami.” The tsunami-source of formation is supported by previous modeling by other authors, which indicated that the geometry of overhanging sea cliffs can greatly strengthen and focus the force of tsunami waves. Additional changes occurred to the island and arch during the 2015–2016 El Niño event, which was one of the strongest on record. During the event, anomalous wave heights and reversed wind directions occurred across the Pacific. On the night of 24–25 February 2016, large storm waves, resulting from the unique El Niño conditions washed out a large boulder that had lain within the arch since its initial formation, significantly increasing the open area beneath the arch. Large waves also rose high enough for seawater to flow over the peninsula at Laie Point, causing significant erosion of its upper surface. These changes at Laie Point and Kukuio’olua Island serve as examples of long-term, intermittent change to a coastline—changes that, although infrequent, can occur quickly and dramatically, potentially making them geologic hazards.

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